﻿#region License
/*
 * Copyright ©2011-2012 EasyMon Project
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *  
 */
#endregion

using System;
using System.Diagnostics;
using EasyMon.Common.Sources;
using EasyMon.Common.Values;
using EasyMon.Win.Agent.Utils;

namespace EasyMon.Win.Agent.Extensions
{
    public static class PerfCounterSourceExtensions
    {
        public static PerfCounterValue Query(this PerfCounterSource source, string processInstanceName)
        {
            try
            {
                var counter = new ReadOnlyPerformanceCounter(
                    source.CategoryName, source.CounterName, source.InstanceName == PerfCounterSource.ProcessInstanceMarker ? processInstanceName : source.InstanceName);

                var value = new PerfCounterValue
                {
                    DisplayName = source.DisplayName,
                    CounterValue = counter.NextValue()
                };

                var displayValue = value.CounterValue;
                if (!double.IsNaN(source.DisplayMultiplier))
                    displayValue *= source.DisplayMultiplier;

                value.DisplayValue = source.DisplayDecimalPlaces >= 0 
                    ? displayValue.ToString("F" + source.DisplayDecimalPlaces) 
                    : displayValue.ToString();

                value.Status = PerfCounterStatus.GetPerfCounterStatus(counter).GetNewValueStatus(source, value.CounterValue);

                return value;
            }
            catch(Exception e)
            {
                Trace.WriteLine(e.ToString());

                return new PerfCounterValue
                {
                    DisplayName = source.DisplayName,
                    Status = ValueStatus.Unavailable
                };
            }
        }
    }
}
